Method and apparatus for in vivo collection of circulating biological components

ABSTRACT

The invention relates generally to in vivo collection of circulating molecules, tumor cells and other biological markers using a collecting probe. The probe is configured for placement within a living organism for an extended period of time to provide sufficient yield of biological marker for analysis. In some embodiments of the invention, active attraction of biological markers are provided. A partial or complete analytic/detection assembly may also be integrated with the probe.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 60/531,928 filed on Dec. 22, 2003, thedisclosure of which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to devices and methods for collectingand/or detecting biological components in vivo over a period of time.Active methods of collecting biological components are also provided.The detection and/or analysis of the biological components collected bythe devices may be performed in vivo or ex vivo.

2. Description of the Related Art

Cancer is one of the leading causes of disease, being responsible for563,700 deaths in the United States each year (Jemal A et al., Cancerstatistics, 2004, CA Cancer J. Clin. 2004 January-February; 54(1):8-29). For example, breast cancer is the most common form of malignantdisease among women in Western countries and, in the United States, isthe most common cause of death among women between 40 and 55 years ofage (Forrest AP, Screening and breast cancer incidence, J Natl CancerInst. 1990 Oct. 3; 82(19): 1525-6.). The incidence of breast cancer isincreasing, especially in older women, but the cause of this increase isunknown. Malignant melanoma is another form of cancer whose incidence isincreasing at a frightening rate, at least sixfold in the United Statessince 1945, and is the single most deadly of all skin diseases (Jemal etal., 2004).

One of the most devastating aspects of cancer is the propensity of cellsfrom malignant neoplasms to disseminate from their primary site todistant organs and develop into metastases. The early spread of viabletumor cells is considered a hallmark in cancer progression. Despiteadvances in surgical treatment of primary neoplasms and aggressivetherapies, most cancer patients die as a result of metastatic disease.Animal tests indicate that a substantial frequency of circulating cancercells from solid tumors establish successful metastatic colonies(Fidler, 1993). Studies have found that the detection of circulatingmetastatic tumor cells and circulating tumor DNA in the blood of cancerpatients correlates with cancer progression. (Hoon D S, et al.,Molecular markers in blood as surrogate prognostic indicators ofmelanoma recurrence, Cancer Res. 2000 Apr. 15; 60(8): 2253-7, and TabackB, et al., Circulating DNA microsatellites: molecular determinants ofresponse to biochemotherapy in patients with metastatic melanoma, J.Natl. Cancer Inst. 2004 Jan. 21; 96(2): 152-6, herein incorporated intheir entirety by reference)

Thus, the detection of occult cancer cells, DNA and tumor markers in thecirculation is important in assessing the level of tumor progression andmetastasis. Because subclinical metastasis can remain dormant for manyyears, traditional surveillance measures such as radiological monitoringwith CT scans or MRI and nodal biopsy may lack the sensitivity to detectearly disease.

Notwithstanding the foregoing, there remains a need for improved methodsand devices for detecting biological components of disease.

SUMMARY OF THE INVENTION

In one embodiment of the invention, a biological surveillance probe fordetecting disease is provided. The probe comprises an elongate bodyhaving a proximal end and a distal end, an attraction structure attachedto the elongate body, wherein the attraction structure is capable ofattracting a binding agent. In some embodiments, the attractionstructure is a magnetizable structure, a microstructure, a nanotubemicrostructure, a metallic microporous structure, or a cavity containinga mixture of polymer gel and magnetizable particles. The probe mayfurther comprise a detection assembly. In some embodiments, thedetection assembly may be an electrical detection assembly, animpedance-based detection assembly, an ion-exchange membrane detectionassembly or a fiberoptic-based assembly. The probe may further comprisea binding agent. In one embodiment, the binding agent comprises anantibody, a fluorescent dye component or quantum dot linked to thebinding agent. In one embodiment, the elongate body comprises astent-like structure. The attraction structure may comprise amagnetizable coating on the elongate body.

In another embodiment, a method for detecting disease is provided. Themethod comprises the steps of providing a binding agent attractiondevice, inserting the device into a body, introducing a binding agentinto the body, attracting at least a portion of the binding agent to theattraction device, and assessing the binding agent attracted to theattraction device. In some embodiments, the introducing step may beperformed by injecting the binding agent into the bloodstream, elutingthe binding agent from an implant within the body or ingestion of thebinding agent into the body. In some embodiments, the assessing step isperformed by impedance-based detection of the binding agent or byoptical detection of the binding agent.

In another embodiment of the invention, a method for detecting diseaseis provided. The method comprises the steps of introducing a bindingagent into the body, attracting at least a portion of the binding agentto a location in the body and assessing the attracted binding agent. Theassessing step may be performed ex vivo or in vivo. The location in thebody may be the position of an attraction device placed within the body.In one embodiment, the binding agent is linked to a fluorescent dye. Theassessing step may be performed by assessing the fluorescence of thefluorescent dye levels of the attracted binding agent.

Several embodiments of the present invention provides these advantages,along with others that will be further understood and appreciated byreference to the written disclosure, figures, and claims includedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and operation of the invention will be better understoodwith the following detailed description of embodiments of the invention,along with the accompanying illustrations, in which:

FIG. 1 is a cross sectional view depicting one embodiment of a probecapable of collecting biological components;

FIG. 2 represents an elevational view of another embodiment of a probewith a guidewire lumen and side port;

FIGS. 3A and 3B are scanning electron micrographs depicting variousembodiments of the invention comprising porous structures;

FIGS. 4A through 4D are micrographs illustrating various configurationsof the micro-porous tube of a probe;

FIG. 5 is a schematic cross sectional view of an active probe with apolymer gel cavity.

FIG. 6 is a cross sectional view of an active probe with a microporoustip.

FIG. 7 is a cross sectional view of an active probe with a microporoustip and an ion-exchange membrane covering.

FIGS. 8A through 8C are schematic views of one embodiment of a probe andan external activation system. FIG. 8A is a schematic cross sectionalview of one embodiment of an external cuff. FIG. 8B is a schematic ofone embodiment of a cuff attached to an external unit. FIG. 8C is aschematic view of the probe and external cuff applied to a patient. FIG.8D is another embodiment of a probe usable with an external activationsystem.

FIG. 9 is a cross sectional view of an active probe with a fiber opticdetection assembly.

FIGS. 10A and 10B depict another embodiment, of the active probe with afiber optic detection assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The detection of occult cancer cells and other biological markers hasshown promise in the diagnosis and treatment of disease. For example,the monitoring of patients' blood for circulating tumor cells and othermarkers may prove advantageous in detecting early tumor progressionbefore metastasis to other organs occurs. Circulating nucleic acids,tumor cells and proteins can be detected in the blood (inclusive ofplasma and serum), bone marrow, cavity fluids and cerebrospinal fluid(CSF) of cancer patients which may serve as risk stratification factors,markers for the presence of clinical disease, predictors of subclinicaland/or minimal residual disease presence, determinants of treatmentresponse and disease progression, and prognosticators of patientoutcome. Other body fluids shown to have the above tumor cells, proteinmarkers, carbohydrate markers or nucleic acids include urine, pleuralfluids and peritoneal fluids (ascites). However, assessment of thesemolecules/tumor cells or components thereof requires a blood sample,which is collected at a single time-point or at multiple time points bydeliberate invasion of body tissue (i.e. needle stick).

These methods are often limited by the intermittent and/or low-levelpresence of cancer cells and markers in the blood. Although newamplification and detection techniques, such as immunochemistry, flowcytometry and reverse transcriptase polymerase chain reaction aid in thedetection of early disease markers, these techniques may fail toovercome sampling errors inherent in the blood draws. Because of theconstant circulating nature of blood and the limited volume in aparticular blood draw, evaluating a single blood sample at onetime-point may not accurately represent the quantity and quality ofcirculating nucleic acids, tumor cells, proteins or other tumor markersfor diagnosis, prognosis and monitoring of disease. Sampling error cancontribute to the frequent false-negative results found withpost-treatment cancer surveillance.

A major problem in detecting tumor cells and tumor markers in blood isthat they are not released at any particular time point. Therefore, theprobability of detecting the presence of tumor cells or markers may varyor may be unpredictable. In addition, it is known that for certainbiological markers, blood flow and release of these markers from tissuesare diurnally related and influenced by physical activity of anindividual (i.e., climbing stairs). Circulating nucleic acids, tumorcells, proteins etc as described above (here to fore termed circulatingmolecules or cells or products will be referred as markers or CMC) mayalso be released transiently into the blood stream by otherphysiological events and external influences. Repetitive samplingwithout repetitive invasive procedures would improve the accuracy andsensitivity of detecting molecules circulating in blood.

CMCs appear to circulate in varying levels/concentrations throughout aperson's disease course as well as during a single day and or inresponse to environmental manipulations such as treatment withchemotherapy, hormonal therapy, immunotherapy and radiotherapy as wellas with administration of medications. The variations in the stabilityof these CMCs found in the blood or other body fluids add to theinherent difficulties of an assay that evaluates blood at a single timepoint. Serial assessment of blood would increase the probability ofidentifying CMCs and therefore improve their utility as prognostic,predictive and diagnostic assays. However, serial assessments ofpatients blood requires repeated patient needle sticks which areimpractical, inconvenient and uncomfortable to the patient.

A more practical and less intrusive approach would be to introduce acollecting device, probe, biomaterial adhesive matrix, chromatographyaffinity surface chip or probe, biochip, or particle into the body thatwould come in direct contact with the blood or body fluid over a periodof time. The device may collect, bind or attract the CMCs of interestover time. This product can then be assessed, in vivo or ex vivo, afteran interval of elapsed time to provide a more accurate evaluation ofthose CMCs. One embodiment of the invention comprises a percutaneouslyinserted device that resides indwelling in the bloodstream and canattract and retain a binding partner such as nucleotides (i.e.: oligos,LNAs (locked nucleic acids), PNAs (peptide nucleic acids), cDNA, nucleicacid probes, chromatographic affinity probes or fragments thereof ortheir derivatives, complementary fragments or larger) antibodies (i.e.:monoclonal, polyclonal, FAb fragments, etc) proteins or any biologicalor synthetic material (i.e. biotin-avidin) that is complementary to theCMC in question and that can be assessed in vivo or ex vivo. The desiredbinding partner(s) are capable of binding the corresponding targetmarker of interest in a manner in a sufficient concentration and mannerthat permits retrieval of the probe after an indwelling sample period oftime for qualitative or quantitative analysis of the marker.

The ex vivo concept is similar to a “dip stick” approach in assessing abody fluid for a particular molecule. The in vivo concept is a like animplantable physiological monitoring device. A device and approach ofsuch nature will provide a great improvement over current methods ofevaluating blood. The evaluation of the CMC can be in the form ofconventional monitoring using established in vitro monitoring systems.For example to detect circulating tumor cells or circulating nucleicacids one can use RealTime quantitative PCR and oligonucleotide arrays.For detection of proteins, one can use enzyme-linked immunosorbent assay(ELISA), chromographic affinity assays, etc. For in vivo monitoring itcan be through electric or thermal related impulses or direct imaging.Such embodiments are described in further detail below.

One alternative to coating or affixing a binding partner to the surfaceof a probe is to introduce a mobile binding agent into the body. Themobile binding agent can circulate through the bloodstream or other bodycompartment while binding to the marker of interest. The mobile bindingagent is then concentrated onto a probe using ferromagnetic,electrostatic, electrical, ionic or other type of force. This scheme hasthe advantage of distributing the binding agent through a larger volumeof distribution in the body. This can increase the effective bindingrate of the binding agent to the marker, which in turn will improve theyield of the detection process and/or reduce the indwelling time for theprobe. The binding agent is then concentrated at a body location forfurther analysis, under in vivo or ex vivo conditions.

Thus, one embodiment of the invention comprises a method for enhancingthe yield of CMC or marker by an attraction and collection probe. Themethod involves introducing a binding agent into the body that iscapable of binding to one or more CMC of interest. The binding agent istypically injected into the body, but diffusion from an elutingcomponent of the probe or a separate eluting implant, ingestion, ortransfer into the body transdermally or by suppository may also bepossible.

In one embodiment, the binding agent is linked to an attractant that iscapable of interacting with an attraction site on a probe to produce anattraction force. The attraction force is capable of causing contact andretention of the binding agent/attractant combination to the attractionsite on the probe. In one embodiment, the combination may be attractedto the probe irrespective of whether the binding agent has bound to aCMC or marker.

Distinguishing between the bound and free binding agent collected by theprobe may be performed by additional processes. For example, the probewith collected binding agent may be removed from the body and ex vivoseparation and analysis of the binding agent may be performed by usingprocesses well known in the art. In another embodiment, the bindingagent/attractant combination may undergo a conformation change oractivation upon binding to a CMC that may alter the attraction of thecombination to the probe.

In another embodiment, the attraction site on the device comprises amicroporous structure that attracts the unbound binding agent to a sitedifferent or deeper within the microporous structure than cannot bereached by the bound binding agent.

In one embodiment, a time period is provided for the binding agent tobind at least a portion of the CMC in the volume and compartment ofdistribution. The implantation time of the attraction probe may beshorter or longer than the time period provided for the binding agent tobind the CMC. This time period may be selected based upon the bindingkinetics between the binding agent and CMC, the kinetics between the CMCand/or binding agent with respect to body tissues and compartments, theanticipated CMC levels in the body, the method of binding agentintroduction into the body, and other factors known to those skilled inthe art. Once bound to the CMC, a probe within the body can be activatedto attract the bound CMC to the probe. Activation of a probe isdescribed in greater detail below. In another embodiment, a probe thatis inherently magnetic and does not require activation may be used toattract the complexes. In another embodiment of the invention, yield ofCMC may be enhanced by reducing interference from substances orcomponents that can affect the binding of the CMC. In one embodiment, anionically charged binding surface provides a repelling force againstcertain classes of interfering materials. In another embodiment, afilter is provided between the body environment and the binding surfaceof the probe. The filter is capable of reducing passage of materialthrough the filter based upon one or more characteristics. Thesecharacteristics include but are not limited to particle size, particlecharge, etc. Embodiments for enhancing the yield of CMC are provided ingreater detail below.

The detection time of the probe may be continuous, over multipleintervals, or event-driven. Inactivating the detection mechanism atother times may reduce fibrin deposition and other deleterious processesduring periods of low yield. For example, increased core bodytemperature or increased serum potassium levels are correlated with celllysis of certain cancers and detection during of these events mayenhance the yield of interval collection and detection schemes. Otherevent-based detection periods may include time period to assess apatient's response to therapy through detection of components related tocellular death. This allows measurement of a patient's response, forexample, to chemotherapy and/or radiation therapy, which can then beoptimized to for treatment effect or to minimize side effects.

This device(s) can be inserted surgically, percutaneously orintravenously into the blood stream, peritoneal cavity or bone marrowsuch that continuous contact with circulating blood, and/or body fluidsis ensured. The product can then be collected for analysis in a routinefashion or monitored over time. Several indwelling devices are currentlyavailable that coexist with the patient that in long-term contact withthe blood and patients body fluids without inducing an adverse reaction.These devices also do not significantly impair everyday patientactivities of daily living. These devices include but are not limited tocentrally or peripherally inserted intravenous catheters, pacemakers andtheir leads, automatic internal converter defibrillators, hemodialysiscatheters, peritoneal catheters and prosthetic grafts.

One example of the proposed device is a coated catheter, guidewire orfilament, chip, biomaterial and/or matrix that can be inserted through acentrally or peripherally placed intravenous catheter or implantablecatheter/material into body fluids such as peritoneal cavity, bonemarrow, cerebrospinal fluid, etc. This device can then dwell incontinuous or intermittent contact with the bloodstream and/or bodyfluids to improve yield of collecting tumor cells and componentsthereof, circulating nucleic acids, and proteins, or other itemspreviously mentioned and/or for prolonged or continuous in vivo or exvivo monitoring of marker presence or activity. Monitoring time can varyin vivo from one to several days to weeks or longer. This may providevaluable information on markers of subclinical and/or minimal residualcancer presence and determinants of treatment response and diseaseprogression. Such devices may also be used to monitor host states forother disease progression patterns, including but not limited toinfectious processes and organ transplant rejection.

The invention described allows for continuous invasive monitoring ofCMCs. Through a percutaneous approach, a catheter can be placed into thevasculature of a patient for continuous monitoring of circulating tumorcells and/or their component. Monitoring of CMCs may have diagnostic andprognostic value in patient care as well as serve as an improvedmechanism for monitoring response to treatment. This indwellingcatheter, for example, may attract one or more complementary substrateswhich can include but are not limited to RNA, DNA, oligonucleotides,proteins, carbohydrates, antibodies, LNAs, PNAs, probes, or anycomponent thereof and/or aforementioned in this application that hasaffinity for binding to the CMC. When the desired substrate is attractedto the catheter, chip or any device mentioned in this context containedtherein, the substrate can be quantified and evaluated for informationthat can be conveyed to a self-embedded or external detector. Inaddition, this catheter or device (including nanoparticles, nanodevices,microfabricated devices, etc) and/or with an associated chip or otherdevice containing complementary substrate to the source(s) foridentification to which contains the attracted substrate of interest canbe removed for ex vivo analysis whereby the information obtained wouldprovide both qualitative and quantitative data.

In addition to enhancing the sensitivity of detecting cancer and cancerrecurrence, the invention allows assessment of circulating tumor cellsand also would provide a rapid monitoring system to determine if aspecific therapy is effective.

In one embodiment of the invention, continuous surveillance/monitoringof circulating nucleic acids (including RNA, double stranded and singlestranded DNA, chimeric RNA/DNA), tumor cells, fetal cells, transplantallogeneic cells, transfected cells, proteins, infectious diseasenucleic acids, proteins, carbohydrates (including glucoproteins,gangliosides and phospholipids) in any complete components or fragmentforms, is performed to assess the presence and/or progression ofdisease. These molecules will be detected in serum, plasma, whole blood,bone marrow, CSF, lymphatic fluid, pleural or peritoneal fluids, urineor other body fluids in patients with cancer, hyperplasia, pregnancy(including prenatal diagnosis), patients with infectious diseasessymptomatic or asymptomatic with other medical conditions such asinfectious disease, autoimmune diseases, inflammatory diseases,cardiovascular disease (including myocardial infarction, unstable anginaand congestive heart failure), neurovascular diseases (e.g., ischemicevents, stroke, anemia), pulmonary disease (including acute respiratorydistress syndromes, fibrosis, pulmonary hypertension, emphysema, asthma,chronic obstructive pulmonary disease), renal disease (infection,hypertension nephropathies, nephritis, renal insufficiency and renalfailure), trauma patients, organ failure, critical care patients, andtransplant patients (including allogeneic and xenogeneic).

A. Binding Partners

The terms “binding partner”, “binding agent” or “member of a bindingpair” refer to molecules that specifically bind other molecules (e.g., amarker of interest) to form a binding complex such as antibody-antigen,lectin-carbohydrate, nucleic acid-nucleic acid, biotin-avidin, etc. Incertain embodiments, the binding is predominantly mediated bynoncovalent (e.g. ionic, hydrophobic, etc.) interactions.

One or more binding partners that specifically bind a target marker tobe detected are attracted to the attraction structure on the probe ofthe invention. The binding partner(s) used in this invention areselected based upon the target marker(s) that are to beidentified/quantified. Thus, for example, where the target marker is anucleic acid the binding partner is preferably a nucleic acid or anucleic acid binding protein. Where the target marker is a protein, thebinding partner is preferably a receptor, a ligand, or an antibody thatspecifically binds that protein. Where the target marker is a sugar orglycoprotein, the binding partner is preferably a lectin, and so forth.A device of the invention can involve several different types of bindingpartners, for example, multiple nucleic acids of different sequenceand/or nucleic acids combined with proteins in the same device. Thelatter would facilitate, e.g., simultaneous monitoring of geneexpression at the mRNA and protein levels. Other combinations ofdifferent types of binding partners can be envisioned by those of skillin the art and are within the scope of the invention. Furthermore, thebinding partner may be combined with an optically sensitive dye tofacilitate assessment of bound CMCs.

Methods of synthesizing or isolating such binding partners are wellknown to those of skill in the art. For example, nucleic acids for useas binding partners in this invention can be produced or isolatedaccording to any of a number of methods well known to those of skill inthe art. In one embodiment, the nucleic acid can be an isolatednaturally occurring nucleic acid (e.g., genomic and/or mitochondrialDNA, cDNA, mRNA, etc.). Methods of isolating naturally occurring nucleicacids are well known to those of skill in the art (see, e.g., Sambrooket al. (1989) Molecular Cloning—A Laboratory Manual (2nd Ed.), Vol. 1-3,Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.).

1. Antibody-Based

Antibodies or antibody fragments for use as binding partners can beproduced by a number of methods well known to those of skill in the art(see, e.g., Harlow & Lane (1988) Antibodies: A Laboratory Manual, ColdSpring Harbor Laboratory, and Asai (1993) Methods in Cell Biology Vol.37. Antibodies in Cell Biology, Academic Press, Inc. N.Y.). In oneembodiment, antibodies are produced by immunizing an animal (e.g., arabbit) with an immunogen containing the epitope to be detected. Anumber of immunogens may be used to produce specifically reactiveantibodies. Recombinant proteins are the preferred immunogens for theproduction of the corresponding antibodies. The antibodies may bemonoclonal or polyclonal. Naturally occurring protein may also be usedeither in pure or impure form. Synthetic peptides are also suitable andcan be made using standard peptide synthesis chemistry (see, e.g.,Barany and Merrifield, Solid-Phase Peptide Synthesis; pp. 3-284 in ThePeptides: Analysis, Synthesis, Biology. Vol. 2: Special Methods inPeptide Synthesis, Part A., Merrifield et al. (1963) J. Am. Chem. Soc.,85: 2149-2156, and Stewart et al. (1984) Solid Phase Peptide Synthesis,2nd ed. Pierce Chem. Co., Rockford, Ill.) Preferably, human or humanizedantibodies are used to prevent host anti-xenogen antibody production.These antibodies may include antibodies derived from hybridomas (tumorcells fused with antibody-producing mammalian cells), humanizedchimerics, Epstein-Barr Virus transformed B-cells and transgenicantibodies.

Methods for producing polyclonal antibodies are also well known to thoseof skill in the art. In one embodiment, an immunogen is mixed with anadjuvant and an animal is immunized. The animal's immune response to theimmunogen preparation is monitored by taking test bleeds and determiningthe titer of reactivity to the immunogen. When sufficient titers ofantibody to the immunogen are obtained, blood is collected from theanimal and an antiserum is prepared. If desired, the antiserum can befurther fractionated to enrich for antibodies having the desiredreactivity. The animal may be a monoclonal mouse, rat, rabbit, chickenor other animal known in the art.

Monoclonal antibodies can be obtained by various techniques familiar tothose skilled in the art. In one embodiment, spleen cells from an animalimmunized with a desired antigen are immortalized, commonly by fusionwith a myeloma cell (See, Kohler and Milstein (1976) Eur. J. Immunol. 6:511-519). Alternative methods of immortalization include transformationwith Epstein Barr Virus, oncogenes, or retroviruses, or other methodswell known in the art. Colonies arising from single immortalized cellsare screened for production of antibodies of the desired specificity andaffinity for the antigen, and yields of the monoclonal antibodiesproduced by such cells can be enhanced by various techniques, includinginjection into the peritoneal cavity of a vertebrate host.Alternatively, DNA sequences encoding a monoclonal antibody or a bindingfragment thereof can be isolated by screening a DNA library from human Bcells according to the general protocol outlined by Huse et al. (1989)Science, 246: 1275-1281. Such sequences can then be expressedrecombinantly.

In one embodiment of the invention, the technique comprises injection ofan antibody or fragment of an antibody (referred to as Ab) into apatient or organism and to use a device that can allow capture ofprotein, circulating tumor cells, DNA or RNA in the blood stream or bodycavity. The device will be able to attract Ab in high density. The Abmay be natural, recombinant (chimeric, Fab, scFv, etc.), or geneticallyengineered. Preferably the Ab will be human to prevent anti-foreignantibody responses (i.e. human antibody response to mouse antibodies;HAMA). The device can be removed after insertion into the blood streamto be monitored for biomarkers or cells it can attract and capture. Theinsertion device can be a catheter, array chip, capture vessel, capturefilter, entrapment or attraction device. The device can be inserted for1, 2, 3, 4 . . . 24 hrs or days or weeks. Monitoring of the capturedbiomarker or cells may be assessed in vivo or ex vivo utilizing knowntechniques depending on the biomarker or cell type. The biomarker orcells captured can be assessed quantitatively or qualitatively. Inanother approach the biomarker or cells captured will be monitored invivo utilizing a signaling indicator based on electrical, colorimetricor activation signals.

In attracting cells to the device, specific Ab that bind to cell surfacemarkers of cancer cells may be used. Cancer cells have distinct markerson their cell surface that distinguish them from normal cells. This hasbeen demonstrated by immunohistochemistry (Racila E et al., Detectionand characterization of carcinoma cells in the blood, Proc Natl Acad SciUSA. 1998 Apr. 14; 95(8): 4589-94). These antibodies can be used totarget epithelial origin cells, tumor cells originated from specifictissues, non-epithelial origin cells (i.e. melanoma). Circulating tumorcells are found in the blood stream and body fluids of cancer patients(Hoon D S, et al., “Detection of occult melanoma cells in blood withmultiple-marker polymerase chain reaction assay” J Clin One. 1995August; 13(8); 2109-16, and Hoon D S, et al., “Molecular markers inblood as surrogate prognostic indicators of melanoma recurrence” CancerRes. 2000 Apr. 15; 60(8): 2253-7). Tumor cells spread to distant organsvia the blood stream, lymphatic ducts or body fluids or body cavities.The spread of tumor cells can eventually lead to tumor growth at distantsites from the original tumor, thus producing metastasis. Growth ofmetatastatic tumor sites can lead to death.

Detection of tumor cells can be used as an indicator of disease spread,tumor aggressiveness, potential to spread to other organs, and presenceof disease in individuals who are otherwise diagnosed as disease-free byconventional means. Detection of tumor cells in vivo may be advantageousin some circumstances over ex vivo detection. The approach will allowbetter capture of early disease. One cannot predict disease spreading orvolume through single blood draw of a small amount of blood or bodyfluid. One approach comprises catching tumor cells through having anattraction and capturing system in the blood stream or body fluid toaccess a larger vascular or fluid volume and/or for a longer period oftime to increase the yield of marker recovered. This is may beadvantageous when capturing occult circulating metastatic or leukemictumor cells. The cell surface marker can be a protein, glycoprotein,glycolipid, peptide epitope, conformational biological epitope ormultiple disease or tumor markers. The device may have more than one Abattached to it to improve sensitivity and capturing ability. The Ab maybe to multiple epitope sites of a single biomarker antigen. The tumorcells captured may be dislodged when the device is removed and assessedby the following ex vivo methods: immuno-histochemistry, DNA, mRNAand/or proteomics. In other embodiments, the binding complexes mayremain on the probe and assessed in situ.

The isolation of the cells may involve physical removal, direct solventremoval specific to that biomarker's physical-chemical properties orcessation of the active attraction force of the probe to release thebinding agent/biomarker complex. For example DNA and RNA from tumorcells can be extracted directly from the tumor cells after isolation.Isolation of DNA or RNA can be by solvents used for nucleic acids. Thiscan be accomplished directly or after the cells have been dislodged. RNAand DNA can be detected by hybridization to a specific probe, polymerasechain reaction (PCR) or related monitoring approach. The assessment ofnucleic acids from the tumor cells can provide quantitative andqualitative analysis. Even if non tumor cells are captured, thespecificity of the analysis can be optionally increased through a secondtier analysis. Sensitivity of the analysis can be further be enhancedthrough amplification of the nucleic acids by PCR or related methods,incorporating specific probes or detection systems ex vivo. Specificityand sensitivity ex vivo for the specific nucleic marker can beapproached using current technologies. The DNA markers may comprisemicrosatellites, mutations, translocations, insertions, amplifications,SNPs or chromatin/DNA complexes. The RNA markers can comprise specificgenes in whole or part in the form of mRNA.

Protein, glycoprotein, or glycolipid analysis can be detected byantibody, mass spectrophotometry, surface enhanced laserdesorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS),matrix-assisted laser desorption/ionisation-time of flight massspectrometry (MALDI-TOF MS), affinity assay, chromatographic approach.The approach can be directly from the device or removal of the biomarkerby some solvent, physical method or reagent to a vessel where it can beprocessed. The detection can be in the form of an affinity matrix chipfor the specific biomarker type.

The Ab used with the device can be a natural antibody produced by humanor some animal B cells in the form of polyclonal or monoclonal antibody.The Ab can be a recombinant antibody that is released from transfectedmammalian or prokaryotic cells. The Ab can be a fragment of an antibodysuch as scFV, FV or Fab fragment that has specific recognition of thebiomarker or cell epitope. The Ab can be a genetically engineered Abthat has a specific attachment moiety or detection ability.

The Ab used with the device can be polyclonal or monoclonal antibody toa specific epitope or multiple epitopes to a specific biomarker orepitope. It can consist of multiple Ab to multiple biomarkers. Thelatter will allow higher sensitivity and capturing ability.

2. Protein-Based

In one embodiment, the binding partner is a binding protein. Suitablebinding proteins include, but are not limited to, receptors (e.g., cellsurface receptors), receptor ligands (e.g., cytokines, growth factors,etc.), transcription factors and other nucleic acid binding proteins, aswell as members of binding pairs, such as biotin-avidin.

Binding proteins useful in the invention can be isolated from naturalsources, mutagenized from isolated proteins, or synthesized de novo.Means of isolating naturally occurring proteins are well known to thoseof skill in the art. Such methods include, but are not limited to,conventional protein purification methods including ammonium sulfateprecipitation, affinity chromatography, column chromatography, gelelectrophoresis and the like (see, generally, R. Scopes, (1982) ProteinPurification, Springer-Verlag, N.Y.; Deutscher (1990) Methods inEnzymology Vol. 182: Guide to Protein Purification, Academic Press, Inc.N.Y.). Where the protein binds a target reversibly, affinity columnsbearing the target can be used to affinity purify the protein.Alternatively the protein can be recombinantly expressed with a HIS-Tagand purified using Ni.sup.2+/NTA chromatography.

In another embodiment, the binding protein can be chemically synthesizedusing standard chemical peptide synthesis techniques. Where the desiredsubsequences are relatively short, the molecule may be synthesized as asingle contiguous polypeptide. Where larger molecules are desired,subsequences can be synthesized separately (in one or more units) andthen fused by condensation of the amino terminus of one molecule withthe carboxyl terminus of the other molecule thereby forming a peptidebond. This is typically accomplished using the same chemistry (e.g.,Fmoc, Tboc) used to couple single amino acids in commercial peptidesynthesizers.

The technique will involve binding of free circulating proteins,peptides or protein complexes via an affinity matrix or antibody orligand (referred to as affinity substrate; AS) that is then attracted toa device and allows capture of proteins, peptides or glycoproteins fromthe blood stream or body cavity. The device can attract the bound AS inhigh density. The device can be removed after insertion into the bloodstream to be analyzed for biomarkers it can capture. The insertiondevice can be a catheter, array chip, capture vessel, capture filter,entrapment device. The device can be inserted for 1, 2, 3, 4 . . . 24hrs or days or weeks. Monitoring of the captured biomarker or cells willbe assessed ex vivo utilizing known techniques depending on thebiomarker type. The biomarker captured can be assessed quantitatively orqualitatively. In another approach the biomarker captured will bemonitored in vivo utilizing a signaling indicator based on electrical,colormetric or activation signals.

Protein and glycoprotein analysis can be detected ex vivo by antibody,mass spectrophotometry, affinity assay, chromatographic approach. Theapproach can be directly from the device or removal of the biomarker bysome solvent, physical method or reagent to a vessel where it can beprocessed.

The antibody used with the device can be a natural antibody produced byhuman or some animal B cells in the form of polyclonal or monoclonalantibody. The antibody can be a recombinant antibody that is releasedfrom transfected mammalian or prokaryotic cells. The antibody can be afragment of an antibody such as scFV, FV or FAb fragment that hasspecific recognition of the biomarker or cell epitope. The antibody canbe a genetically engineered antibody that has a specific attachmentmoiety or detection ability.

The AS can be in the form of affinity matrix material that is specificor non-specific for particular protein properties. The former ispreferable. For non-specific affinity matrix materials (not to aspecific biomarker), the AS can be based on charge to attracthydrophilic or hydrophobic molecules. The antibody or ligand substrateattracted by the device can be directed towards a specific epitope ormultiple epitopes to a specific biomarker. It can comprise multiple ASto multiple biomarkers. The latter will allow higher sensitivity andcapturing ability.

Optionally, a chip-based detection system may be used. For example,DNA/oligonucleotide chip detection involves attachment or incorporationof a chip into a device to be inserted into the blood stream or bodycavity. The assessment of components attracted to the chip may beperformed in vivo directly through electronic or chemical signaling orex vivo by a detection device. For DNA analysis this will includemicrosatellite analysis for loss of heterozygosity (LOH) or by singlenucleotide polymorphism (SNP). Other genomic DNA markers can includemutations, amplifications and translocations. The analysis may involvespecific or multiple sites of the chromosomal or mitochondrial DNA fromtumor cells. RNA analysis will involve assessment of mRNA of transcriptsof specific genes related to the tumor cells. The mRNA transcript may beof the whole or part of the full transcript or a truncated derivative ofthe transcript. The procedure may also include chromatin and DNAcomplexes (histone proteins) related to specific genomic regions oftumor cells. The procedure may encompass assessing acetylation anddeacetylation of chromatin regions of specific genomic regions,methylated or non-methylated. The procedure may encompass assessingmethylated or non-methylated regions of the genomic regions such aspromoter related-regions of tumor-related genes. The chip may beinserted for 30 min, 1, 2, 3 . . . 24 hr and removed for assessment orassessed directly.

B. Attraction of Binding Partner to Probe

As previously mentioned, the desired binding partner(s) are attracted tothe attraction structure or site on the probe in a sufficientconcentration and manner to be capable of binding the correspondingtarget marker of interest. The attraction is performed in a manner thatpermits retrieval of the probe after an indwelling sample period of timefor qualitative or quantitative analysis of the marker. In oneembodiment, the linkage between the binding partner and the attractionor substrate surface on or attached to the probe is magnetic, but otherattraction mechanisms may also be used. Various embodiments of anattraction system are provided in greater detail further below.

C. General Probe Configurations

Referring to FIG. 1, there is disclosed a CMC or marker binding andretrieval probe 10 in accordance with one aspect of the presentinvention. Although the probe 10 will be described primarily in terms ofan insert to be temporarily placed down an existing access port orsheath into the cardiovascular system, for retrieving a marker fromblood, the present inventors contemplate broader applicability as willbe apparent to those of skill in the art in view of the disclosureherein. Existing access ports or sheaths include but are not limited toHickman catheters, Portacath catheters, peripherally inserted centralcatheter (PICC) lines, femoral, jugular, or subclavian central venouslines, radial arterial catheters and peripheral venous lines.Furthermore, procedures such as transseptal puncture and transjugularintrahepatic puncture, may be used to access other body sites such asthe arterial chambers of the heart or the portal vein, respectively.

For example, the probe may be adapted for direct access to a targetsite, without the use of a distinct tubular access catheter. In general,whether used with an access sheath or as a stand alone device, thedimensions of the probe can be optimized by persons of skill in the artin view of the present disclosure to suit any of a wide variety oftarget sites. For example, the probe of the present invention can beused to obtain samples from large and small arteries and veinsthroughout the cardiovascular system, as well as other lumens, potentialspaces, hollow organs and surgically created pathways. Marker collection(tumor and/or non-tumor) may be accomplished in blood vessels, bodylumens or cavities, such as the lymphatic system, esophagus, trachea,urethra, ureters, fallopian tubes, intestines, colon, biliary ducts,spinal canal and any other locations accessible by a flexible or rigidprobe which may contain a specific binding partner of diagnostic value.The probe 10 may also be adapted for direct advance through solidtissue, such as soft tissue or through bone, for site specificmonitoring of a binding partner of interest.

The probe 10 generally comprises an elongate body 16 extending between aproximal end 12 and a distal functional end 14. The length of the body16 depends upon the desired access site and the desired placement sitefor the distal end 14. For example, lengths in the area of about 1 cm toabout 20 or about 30 cm may be useful in applications that require thecatheter to be advanced down a relatively short tubular access sheath.Longer lengths may be used as desired, such as on the order of fromabout 120 cm to about 140 cm for use in percutaneous access at thefemoral artery for placement of the distal end 14 in the vicinity of thecoronary artery. Intracranial applications may call for a differentcatheter shaft length depending upon the vascular access site, as willbe apparent to those of skill in the art.

Many markers of interest, however, may be equally retrievable at anypoint throughout the cardiovascular system, in which case the probe 10may be adapted to advance down any convenient access port that may havebeen placed for other diagnostic or therapeutic use. Devices inaccordance with the present invention may also be adapted for exposureto blood by coupling to any of a variety of ports on extracorporealcirculation systems as will be apparent to those of skill in the art inview of the disclosure herein.

In the illustrated embodiment, the body 16 is divided into at least aproximal section 33 and a distal binding zone 34. In general, distalbinding zone 34 is adapted to carry a attraction structure for themarker of interest, as discussed previously, and may or may not beotherwise structurally distinct from the proximal section 33.

At least a portion of the proximal section 33 of body 16 may be producedin accordance with any of a variety of known techniques formanufacturing catheter bodies, depending upon the desired clinicalperformance. For example, the body 16 may be formed by extrusion of anyof a variety of appropriate biocompatible polymeric materials. Knownmaterials for this application include high density polyethylene,polytetrafluoroethylene, nylons, PEEK, PEBAX and a variety of otherssuch as those disclosed in U.S. Pat. No. 5,499,973 to Saab, thedisclosure of which is incorporated in its entirety herein by reference.Alternatively, at least a proximal portion or all of the length of body16 may comprise a spring coil, solid walled hypodermic needle tubing, orbraided reinforced wall, as is understood in the catheter and guidewirearts. Whether metal or polymeric or a hybrid, the body 16 may be hollowor solid depending upon the nature of the binding system and otherdesired capabilities.

In one cardiovascular example, the body 16 is provided with anapproximately circular cross-sectional configuration having an externaldiameter within the range of from about 0.025 inches to about 0.100inches. In accordance with one embodiment of the invention, the body 16has an average external diameter of about 0.042 inches (4.2 f)throughout most of its length. Alternatively, generally rectangular,oval or triangular cross-sectional configurations can also be used, aswell as other noncircular configurations, depending upon the method ofmanufacture, desired surface area, flexibility, access pathway and otherdesign considerations that may be relevant for a particular application.

Dimensions outside of the ranges identified above may also be used,provided that the functional consequences of the dimensions areacceptable for the intended purpose of the catheter. For example, thelower limit of the cross section for any portion of body 16 in a givenapplication will be a function of the number of fluid or otherfunctional lumens, if any, contained in the probe, together with thedesired surface area to be available for the binding partner, as will bediscussed.

Probe body 16 should also have sufficient structural integrity (e.g.,column strength or “pushability”) to permit the probe to be advanced toa desired target site without buckling or undesirable bending.

The proximal end 12 of the probe 10 may be provided with a grip 46 suchas a polymeric cap 48 which may be molded or otherwise secured to theproximal end 12 of the body 16. Preferably, the cap is provided with acomplementary surface structure to allow a removable connection betweenthe cap and the proximal end of an intravenous catheter or other devicethrough which the probe 10 will achieve contact with blood or other bodyfluid. Removable attachment may be accomplished by using any of a widevariety of clips, twist fasteners such as Luer connectors, interlockingsnapfit connectors, or friction fit connectors as will be appreciated bythose of skill in the art in view of the disclosure herein.

The axial length of the probe 10 is preferably precisely calibrated tomatch the particular access catheter with which it is to be used, toprovide a reproducible length of the binding zone to be exposed to thesample of interest.

Referring to FIG. 2, there is disclosed another embodiment of probe 10.The proximal end 12 of probe 10 is provided with a manifold 18 havingone or more access ports as is known in the art. Manifold 18 may beprovided with a guidewire port 20 in an embodiment where over-the-wirenavigation of the probe may be desired. An infusion port 22 may beprovided with or without the guidewire port. The infusion port is influid communication with the binding zone through an infusion lumen.This allows periodic or continuous infusion of saline, heparin or othermedia to prevent “clogging” or coating of the binding zone over time, bynatural clotting or other processes which may interfere with theefficacy of the binding chemistry. Additional access ports may beprovided as needed, depending upon the desired capabilities of thecatheter. Manifold 18 may be injection molded from medical gradeplastics or formed in accordance with other techniques known in the art.

The distal end 14 of the probe 10 may be provided with an atraumaticdistal tip 25 which may include a guidewire exit port 26 in a guidewirelumen embodiment as is known in the art. A radiopaque marker (notillustrated) may be provided on the probe body 16 in the case ofrelatively long probes to facilitate positioning of the probe as isknown in the art. Suitable marker bands can be produced from a varietyof materials, including platinum, gold, and tungsten/rhenium alloy.

The distal zone of the probe is provided with an attraction structure,capable of attracting a marker of interest. As used herein, the termmarker refers to any CMC discussed above, as well as any other cell,cell fragment, protein, peptide, glycoprotein, lipid, glycolipid,proteolipid, or other molecular or biological material that is uniquelyexpressed (e.g. as a cell surface or secreted protein) by diseasedcells, or is expressed at a statistically significant, measurablyincreased or decreased level by diseased cells, or in association with adisease state of interest (e.g. a protein expressed by an infectiousagent associated with disease), or is expressed at a statisticallysignificant, measurably increased or decreased level by diseased cellscompared to normal cells, or which is expressed by non-diseased cells inassociation with disease (e.g. in response to the presence of diseasedcells or substances produced therefrom). Disease markers can alsoinclude specific DNA or RNA sequences marking a deleterious geneticchange, conformational change compared to baseline or normal, or analteration in patterns or levels of gene expression significantlyassociated with disease. Disease markers include breast cancer markers.

The term cancer marker refers to a subset of disease markers, namely anyprotein, peptide, glycoprotein (including but not limited to mucins,mucoid and amyloid glycoproteins), lipid, glycolipid, proteolipid, orother molecular or biological material that is uniquely expressed (e.g.as a cell surface or secreted protein) by cancerous cells, or isexpressed at a statistically significant, measurably increased ordecreased level by cancerous cells compared to normal cells, or which isexpressed by non-cancerous cells in association with cancer (e.g. inresponse to the presence of cancerous cells or substances producedtherefrom). Cancer markers can also include specific DNA or RNAsequences marking a deleterious genetic change, conformational change,or an alteration in patterns or levels of gene expression significantlyassociated with cancer.

a. Attraction Structure

The attraction structure may be configured with an increased surfacearea to provide an increased number of interaction sites on the probe.The surface area may be increased by providing an increased longitudinallength, increased diameter or cross-section through at least a portionof the distal zone. In addition, or alternatively, at least a portion ofthe distal zone may comprise a porous material and/or microstructure toincrease the surface area. Non-limiting examples of porous materialsinclude porous polymers, ePTFE, PTFE, polyurethane, silicone, foam, or aceramic with a porous surface (e.g., titanium nitride, titanium carbide,carbon, and silicon carbide). Various techniques for depositing materialon the probe surface to provide a porous structure may also be used andinclude ion beam deposition, sintering, sputtering, ion implantation,laser surface alloying, electroplating, physical or chemical vapordeposition, chemical or physical etching, grit blasting, plasma andthermal spray coating. Other materials that can be applied to the probesurface include iridium oxide, graphite and platinum black. The surfacearea may be increased through microstructures on the binding zonesurface, formed from processes including but not limited to mechanicalroughening of the probe surface, laser drilling or metal sintering ontothe probe. The probe may also be manufactured using microporous tubing,porous fabric or and polymers, or carbon fiber bundles, and nanotubes.The surface area of the binding zone may be configured by one skilled inthe art depending upon the expected release pattern, degradation andmetabolization pathways and binding kinetics of the CMCs of interest.

FIGS. 3A and 3B represent scanning electron micrographs (SEM) of variousporous configurations that provide an increased surface area for theprobe. FIG. 3A depicts one embodiment of the invention comprising amicroporous zone formed by vapor deposition. FIG. 3B depicts anotherembodiment of the invention formed with sintered metal beads. Oneskilled in the art will understand that a variety of metals may by usedfor a sintered porous surface, including but not limited to platinum,platinum/iridium and other platinum group metals or alloys thererof,titanium, titanium alloys and 316L stainless steel. In one embodiment,the sintered metal zone has an average pore size of about 5 microns toabout 150 microns to allow particle access into the microporousstructure. In other embodiments, an average pore size of about 5 micronsto about 100 microns may be used. In one example, a sintered metalporous zone has an average pore size of about 10 microns to about 50microns. Microporous structures will typically have a porosity betweenabout 10% to about 80%. In some embodiments, the porous layer has aporosity of about 10% to about 60%, and preferably about 40%.

Other binding zone structures that increase the surface area are shownin FIGS. 4A through 4D. FIG. 4A is a photograph of a porous fabric. FIG.4B depicts a porous polymer. FIG. 4C depicts laser drilled holes in apolymer surface and FIG. 4D depicts a nanotube microstructure forproviding an increased surface area.

b. Magnetic Attraction

One embodiment of the invention utilizes placement of an indwellingmetallic device into the circulatory system or other body organ whichcan conduct electromagnetic current. The device may be regulated andmonitored from an ex vivo source. Intravenous injection of magneticbeads or particles coupled to complementary nucleotides (i.e.: oligos,CpG motifs, LMAs, peptide nucleic acids (PNAs), cDNA, probes, nucleicacid sequences or fragments thereof or their derivatives, complementaryfragments or larger) antibodies (i.e.: monoclonal, polyclonal, Fabfragments etc) proteins (i.e.: albumin, prealbumin) or any biological orsynthetic material (i.e. biotin-avidin). These complementary bindingpartners can bind circulating tumor cells or any disease-associatedcomponents thereof that may be in body. The indwelling venous catheteris induced with electromagnetic current to bring the magnetic particlecomplexed to the CMC of interest in contact with the indwelling/insertedcatheter monitoring device. In one embodiment, a second antibody to thatis complementary to the tumor cell and or its components which carries afluorescent label would be brought into the vicinity of the catheter byits complementary binding to the substrate, bringing the fluorescentmolecule in proximity to the catheter which could optically detect thefluorescence and convert this to a quantitative readout that correspondsto the amount of circulating tumor cells or its components present.These and other embodiments of the invention are described in greaterdetail below.

FIG. 5 depicts one embodiment of the invention comprising a method ofdetecting CMC bound to a collection probe. The collection probe 100comprises an elongate body 102 have a proximal end 104 and a distal end106. A cavity 108 containing a polymer gel 110 is located on theelongate body 102. The cavity 108 is typically located at the distal end106 of the elongate body 102, but may also be located at other positionsalong the length of the probe 100. The probe 100 may have more than onecavity. The cavity 108 may have any of a variety of shapes sufficient tohold a volume of polymer gel, including but not limited to a spherical,box-like, cylindrical, conical or frusta-conical shape. The cavity 108may have an axial cross sectional shape, as measured with respect to thelongitudinal axis of the probe, of about 0.4 mm² to about 5 mm², andpreferably about 1 mm² to about 2 mm². The cavity 108 may have alongitudinal length of about 2 mm to about 10 mm, and preferably about 2mm to about 3 mm. The material defining the cavity 108 and elongate body102 may be any of a variety of materials used in the art for catheterbodies, including but not limited to high density polyethylene,polytetrafluoroethylene, nylons, PEEK, PEBAX and a variety of otherssuch as those disclosed in U.S. Pat. No. 5,499,973 to Saab, thedisclosure of which is incorporated in its entirety herein by reference.In some embodiments of the invention, the materials used haveelectrically insulative properties. In some embodiments, the materialsused have a hardness of about 30A to about 60A, preferably about 20A toabout 40A. The polymer gel 110 may comprise silicone, polyurethane,hydrogel, PLA or any other porous polymer gel known in the art. Thepolymer gel is mixed with any of a variety of conductive particles,including but not limited to carbon, metal or a metallic metal. Thedistal ends 112 of two or more lead wires 114, 116 are in contact withthe polymer gel 110 in the cavity 108 and run along the length of theelongate body 102 of the probe 100 and terminate at the proximal end 104of the elongate body 102 at one or more electrical connectors 118. Thelead wires 114, 116 will typically comprise copper or Monel electricalwire with a diameter of about 30 AWG to about 50 AWG. One skilled in theart will understand that any of a variety of electrical wires may beused for the invention. The wire may optionally have a Teflon orpolyimide insulation coating, generally about 10 micron to about 100micron in average thickness. The electrical connector is configured toattach to an electrical current generator and current measuring system120. The electrical connector 118 may be a standard connector as knownby those with skill in the art, or a proprietary connector. Theelectrical connector 118 may also be of a high-impedance and/orhigh-leakage isolation type of connector. In other embodiments, theelectrical current generator and current measuring system 120 isdirectly connected to the lead wires 114, 116 and an electricalconnector 118 is not required. The electrical current generator andcurrent measuring system 120 may be configured to measure electricalresistance in the range of about 10 Ohms to about 100 K Ohms and run ona AC or DC voltage system of about 2V to about 50V. One skilled in theart may select and/or configure the electrical current generator andcurrent measuring system 120 to the particular embodiment of theinvention.

To use one embodiment of the invention, the patient is injected with amagnetically labeled antibody with at least some specificity for the CMCof interest. The magnetic label of the antibody comprises iron orferrite based beads with about a 2 micron to about a 10 micron particlesize. The impedance-based probe is inserted into the circulatory systemof the patient and the electrical current generator and currentmeasuring system is activated. The electric circuit generates a magneticfield within the polymer gel of the probe that is capable of attractingthe magnetically linked antibody or binding partner. In someembodiments, the magnetically linked antibody or binding partner lodgesin the polymer gel as they are attracted to the magnetic field. In otherembodiments, the magnetically linked binding partner remains in contactwith the polymer gel primarily by the magnetic field and may releaseback into the body circulation if the magnetic field is shut off. Insome embodiments, the measurement of the electrical resistance can beused to determine the duration that the probe is left in the patientand/or electrical generator is activated. As the bound or unboundantibodies are attracted, the changes in the electrical resistance asmeasured through the gel may indicate when all or a sufficient amount ofantibody has been collected. The probe is removed from the patient. Theantibody bound to a CMC of interest is separated from the probe ordifferentiated from the unbound antibody and analyzed. Separating and/ordistinguishing a bound binding partner from an unbound binding partneris well known in the art. In some embodiments of the invention, theunbound antibody is separated from the probe while the CMC-boundantibody remains on the probe. An impedance measurement system may thenbe used to analyze the presence of remaining bound antibody on theprobe. Impedance based detection of biological product is furtherdescribed by Lee et al in U.S. Publication No. 2004/0100284A1, hereinincorporated in its entirety by reference.

Referring to FIG. 6, in another embodiment of the invention, amagnetizable microporous structure 122 is provided rather than a cavityfilled with polymer gel. The lead wires 114, 116 of the probe 100contact the microporous structure 122 and are capable of creating amagnetic field using the microporous structure 122. The lead wires 114,116 may also be integral with the microporous structure 122. Themicroporous structure typically comprises one or more metals such asplatinum, or platinum/iridium (90/10% to about 80/20%), 316L stainlesssteel or titanium (CP grade 1 to 4). One skilled in the art willunderstand that other magnetizable microporous structures may be used.The microporous structure 122 will typically have a cross-sectional areaof about 0.25 mm² to about 5 mm², and preferably about 1 mm² to about 2mm². The cavity may have a longitudinal length of about 1 mm to about 10mm, and preferably about 2 mm to about 3 mm. The microporous structure122 will typically have a porosity of about 10% to about 60%, andpreferably about 40%, with a particle size ranging from about 5 micronsto about 100 microns. The use of the magnetizable microporous probe issimilar to that described previously for the polymer gel embodiment ofthe invention. During magnetic attraction of the magnetically labeledantibody, the bound and unbound antibody may or may lodge within themicroporous structure of the probe.

In another embodiment of the invention, depicted in FIG. 7, themicroporous structure 122 is covered with an ion-exchange membrane 124that is selectively permeable based upon one or more characteristics,including but not limited to particle size and ionic charge. In oneembodiment, the membrane 124 has a thickness of about 20 microns toabout 150 microns, and a pore size of about 40 microns to about 100microns. One skilled in the art can select a particular membraneconfiguration based upon the desired filtering characteristics. Forexample, Nafion (DuPont, Del.) is a synthetic polymer membrane withionic properties that can be used to provide relative increasedpermeability to circulating tumor cells of cDNA.

In another embodiment of the invention, illustrated in FIGS. 8A through8C, the probe 100 comprises a magnetizable attraction site 123 which cangenerate a magnetic field by applying one or more other magnetic fieldsabout the site 123. The other magnetic fields may originate from magnetsexternal to the patient's body that are positioned adjacent to the probe100. Referring to FIG. 8A, in one example, one or more magnetic strips125 are attached to a cuff 127 or other positioning system. The magnetstrips 125 may be permanent magnets or activatable electromagnets. FIG.8B depicts a cuff 127 with electromagnetic strips 129 powered by anexternal unit 131 through lead wires 133. The external unit 131 may alsocomprise a display 135 providing electrical current information to theelectromagnetic field and/or data regarding detection of theferromagnetic particles bound to the CMC of interest. Referring back toFIG. 8A, the cuff 127 or positioning system may be made from flexiblematerial to allow close proximity between the magnets 125 and theattraction site 123. A securing assembly, such as a Velcro strip 137,may be used to secure the cuff 127 to the patient's body. As shown inFIG. 8B, the probe 100 with a magnetizable site 123 is positioned withinthe body and a magnetically labeled binding partner is introduced intothe blood stream, body cavity or body lumen. The cuff is applied to thebody at a location sufficient for the strips to generate a magneticfield at the attraction site and to draw the magnetically labeledbinding partners.

The cuff or external securing system may optionally comprise one or morecoils or loops that can act as a metal detector system to monitor thedegree of concentrated antibody in the region of the cuff and probe.Metal detection systems are well known in the art and may be configuredas very low frequency (VLF), pulse induction (PI) and beat-frequencyoscillation (BFO) metal detection systems. In one embodiment, moresensitive metal detection configurations, such as VLF or PI, arepreferred.

In another embodiment of the invention, depicted in FIG. 8D, themagnetizable probe 150 is configured so that it is capable ofimplantation within the body and does not require a permanent proximalattachment for manipulation and/or retrieval of the probe 150. Adetachable or implantable probe 150 may be beneficial where detection ofa CMC requires prolonged exposure to the body, but the probe 150 is notlimited to this particular use. By detaching from its delivery tool,contact between the probe and the external surface of the body and theprobe surface area within the body may be reduced. This may decrease therisk of thrombogenicity and/or infection created by the presence of theprobe 150. Those with cancer or a history of cancer or other disease maybe predisposed to clot formation and infection and may benefit fromadditional measures to reduce such risks.

In one embodiment, the probe 150 comprises a magnetizable zone and anengagement interface for reversibly engaging a delivery/retrieval tool.The magnetizable zone may comprise a magnetic coating on the probe 150.The engagement interface comprises a mechanical or friction interfacecapable of forming a mechanical or friction fit with adelivery/retrieval tool to facilitate implantation and removal of theprobe. The engagement interface may be further configured to orient theprobe with respect the delivery/retrieval tool to facilitate positioningand removal of the probe through narrow openings such as a blood vessel.The probe may optionally comprise an anchor system for maintaining theposition of the probe in a general or particular location.

As shown in FIG. 8D, in one embodiment, the probe 150 has a stent-likeconfiguration. The probe 150 may be self-expanding orballoon-expandable. One skilled in the art will understand that any of avariety of stent structures, configurations and materials may be used,including but not limited to nitinol, 316L stainless steel, platinum orplatinum/iridium. The probe 150 may be dimensioned for placement in anyof a variety of locations, including but not limited to cardiovascularsystem, a peripheral vein or artery, biliary system, urinary tract,gastrointestinal tract and other lumens or body cavities, natural orartificial. In one embodiment, the probe 150 has an average diameter ofabout 0.5 mm to about 2 mm. In another embodiment, the probe 150 has anaverage diameter of about 1 mm to about 8 mm. The probe 150 may have alength of about 5 mm to about 60 mm. In another embodiment, the probe150 a length of about 10 mm to about 30 mm.

Stent retrieval is known in the art and may be performed in severalways. Representative patents include but are not limited to U.S. Pat.No. 6,569,181 to Burns and U.S. Pat. No. 6,187,016 to Hedges et al.,herein incorporated in their entirety by reference. The stent supportmay further comprise one or more engagement elements to facilitateretrieval of the stent from the body by a retrieval tool.

In another embodiment of the invention, a fiberoptic detection system isprovided to detect bound CMC. Referring to FIG. 9, the probe 100comprises a probe body 126 having a proximal end 128 and a distal end130. A polymer gel cavity 108 is located on the probe body 126,typically about the distal end 130 but other locations may also be used.Two or more optical fibers 132, 134 are located between the proximal end128 of the probe body 126 and the polymer gel cavity 108. At least onefiber is an illumination fiber 132 for providing light to the polymercavity. At least one other fiber is a detection fiber 134 used toanalyze the light found in the polymer cavity. Optical fibers are wellknown in the art and often comprise glass or plastic fibers made fromlow OH silica, quartz or nylon. The fibers may be single or multi-modefibers and have a diameter of about 2 microns to about 200 microns. Thefibers may or may not include a polyimide or Teflon jacket. Additionalinsulation materials 136 or tubing may be used about the optical fibersfor additional protection or to block stray light. The insulation 136can be a polymer material, including but not limited to PTFE,polyurethane, nylon or polyimide. In one embodiment, a molded, adhesiveback-filled or separate tube with a diameter of about 250 microns may beused. The proximal ends 138, 140 of the optic fibers 132, 134 terminateat one or more fiberoptic connectors 142. Standard SMA connectors may beused, but other standard or proprietary connectors may be substituted.The connectors are configured to plug into a monitoring system 144comprising an illumination lamp to provide a light source for theillumination fiber 114, a detection system for analyzing the lightspectrum within the cavity, and a display monitor for displaying theproviding information regarding the probe. One skilled in the art canconfigure each of these and other components of the detection system fora particular purpose.

To detect the binding partner(s) attracted or collected by the probe,any of a variety of optically detectable components may be linked to thebinding partner(s). In one embodiment, the binding partner comprises afluorescent dye is attached to an antibody or other type of bindingpartner. Fluorescent dye labeled antibodies are well known in the art.

In another embodiment, the binding partner for the CMC of interest isoptionally linked to a quantum dot. Quantum dots are small crystals witha particle size of about 10 nanometers or more that flow when they arestimulated by ultraviolet light. The wavelength, or color, of the lightdepends on the size of the crystal. Latex beads filled with thesecrystals can be designed to bind to specific DNA sequences. By combiningdifferent size quantum dots within a single bead, the quantum dotbinding partners can release distinct colors and intensities of light bythe detection fiber of the fiberoptic probe.

FIGS. 10A and 10B depict another embodiment of the invention comprisinga fiber optic detection system, wherein a microporous membrane or layer146 or coating is utilized, rather than a polymer gel cavity. The porousmembrane 146 may be a polymeric, metallic or ceramic, but is preferablya porous polymer gel such as a silicone or polyurethane. The polymerlayer 146 is at least about 2 mm to about 6 mm in length with athickness of about 2 microns to about 100 microns and a porosity ofabout 10% to about 60%. The polymer used generally has a hardness ofabout 30A to about 60A.

In one embodiment, a method for using a fiberoptic probe in a patient isprovided. The probe is inserted into the vasculature of the patient.Antibody linked to a quenching agent is injected into the vasculatureand allowed to bind to a CMC. Binding of a CMC to the antibody causes ashift in the energy spectrum of the quenching agent, thereby causing adetectable wavelength shift when exposed to light from the illuminationfiber of the probe. The detection fiber is able to sense the wavelengthshift and transmit the optical information the display and detectionsystem.

In other embodiments, a combined fiberoptic and impedance systemdetection system is provided in the probe to detect more than one CMC orto enhance the reliability of the detection scheme.

In one embodiments of the invention, the probe further comprisesadditional sensor assemblies to detect other characteristics of theprobe environment or CMC. Information from these other sensor assembliesmay be used to further refine the CMC collection or detection or toprovide complementary information. These other sensor assemblies mayinclude but are not limited to a temperature probe, pH sensor orfiberoptic sensor for assessing other factors such as glucose orpotassium levels. A fluid reservoir may be provided adjacent to themicroporous structure to further assist with CMC detection. Thereservoir may contain certain chemicals, enzymes or other agents thatare part of these other sensor assemblies. Examples include but are notlimited to a pH sensitive gel or fluid.

Other molecules or components may be bound to the probe to facilitate orsupport the function of the attraction structure. In one embodiment,heparin is bound to the probe to resist thrombus formation that mayaffect the function of the attraction structure with extended exposuretime to the body. Heparin coating of medical devices is well known inthe art, as described by Hsu et al. in U.S. Pat. No. 5,417,969, hereinincorporated in its entirety by reference. In another embodiment, astreptokinase coating is provided to resist clot formation (Niku S D etal., Isolation of lymphocytes from clotted blood, J Immunol Methods.1987 Dec. 4; 105(1): 9-14, herein incorporated by reference). Othermaterials that may be bonded to the probe include but are not limited tohydrogels or other lubricious coatings, as described by Hostettler etal. in U.S. Pat. No. 5,919,570, and antimicrobial agents, as describedby Raad and Sherertz in U.S. Pat. No. 5,688,516, herein incorporated intheir entirety by reference. An antimicrobial component may reduce therisk of probe colonization by infectious bacterial and fungal organismsfor a probe placed into a body for an extended period of time. Suchantimicrobial agents may include but are not limited to aminoglycoside,amphotericin B, ampicillin, carbenicillin, cefazolin, cephalosporin,chloramphenicol, clindamycin, erythromycin, gentamicin, griseofulvin,kanamycin, methicillin, nafcillin, novobiocin, penicillin, polymyxin,rifampin, streptomycin, sulfamethoxazole, sulfonamide, tetracycline,trimethoprim, and vancomycin.

The probe may further comprise an optional elution zone capable ofretaining and releasing one or more substances such as drug compounds,reagents or other substances. In one embodiment, the elution zonereleases a substance that enhances release of a CMC from the body. Inanother embodiment, the elution zone releases a substance thatfacilitates detection of a CMC, including but not limited to Ab labeledfluorescent dyes. In still another embodiment, the elution zone releasesa substance capable of reducing a body's immune response to an antigenicelement on the probe. In another embodiment, the elution zone is capableof releasing one or more treatment agents for reducing fibrin depositiononto the binding zone and other portions of the probe. Fibrin depositionmay decrease or affect the binding of CMCs to their binding partnersinto the binding zone. Agents that may be released from the elution zoneinclude but are not limited to dexamethasone, paclitaxel, unfractionatedheparin, low-molecular weight heparin, enoxaprin, syntheticpolysaccharides, ticlopinin, dipyridamole, clopidogrel, fondaparinux,streptokinase, urokinase, r-urokinase, r-prourokinase, rt-PA, APSAC,TNK-rt-PA, reteplase, alteplase, monteplase, lanoplase, pamiteplase,staphylokinase, abciximab, tirofiban, orbofiban, xemilofiban,sibrafiban, roxifiban, bivalirudin, and pentoxifylline.

D. Insertion and Placement of Collection Probe

The collection probe may be inserted in a variety of ways and to avariety of locations within the body. In some situations, the probe maybe inserted during a cancer surgery where access to sentinel sites ofdisease recurrence is readily accessible. For instance, following amastectomy and axillary node dissection for breast cancer, a collectingprobe may be implanted during the same procedure into the lymphaticducts draining the breast. Such as site may provide earlier detection ofrecurring disease and may also increase the yield from suchsurveillance. Similarly, placement of the collection probe surgicallymay also allow or subcutaneous implantation into a large vein while thepatient is still under anesthesia, thereby decreasing the risk ofinfecting the device compared to percutaneous insertion.

The device may also be configured for percutaneous insertion. Someembodiments of the device allow insertion of the probe into existinglong-term access sites such as a Hickman catheter, Portacath, or aperipherally inserted central catheter (PICC) line or variants thereof.Similarly, the probe may also be configured for insertion throughcentral venous catheters inserted into the femoral or jugular vein, orlarge-bore IV access site. For example, a Portacath is an implantablevenous access device that is frequently used in cancer patients toprovide long-term vascular access for chemotherapy. A detection probeplaced into a Portacath or a Portacath variant may serve a dual functionof treating the cancer and provide the ability to monitor treatmenteffect.

In use, a probe having at least one binding partner is provided. Theprobe is advanced to a site where a binding zone on the probe will beexposed to a carrier such as blood which may periodically contain amarker of interest. The probe is left in place for an evaluation period,to allow the marker to become bound to the binding partner. The probe isthereafter withdrawn, and evaluated to determine the presence of anymarker carried by the binding zone.

In one application, the probe is advanced through an access tube toposition the binding zone at an intralumenal site within an artery orvein. The binding zone is left at the site for an evaluation period ofgenerally at least about one hour, in come applications at least aboutfour or six hours, and for certain markers at least about 12 hours or 24hours or more. This allows collection of at least a first quantity of atarget marker from a first release of marker into the blood, and incertain applications at least also a second quantity of the targetmarker from a second release of marker into the blood, the first andsecond releases separated in time from each other. The first and secondquantities of the target marker may be collected on the same probe.Alternatively, during the evaluation period, a first probe may bewithdrawn from the site and replaced by at least a second probe, whichcarries the same or a second binding partner.

The device may be inserted through any of a variety of access methodsknown to interventional radiology, cardiology, gastroenterology andother medical and veterinary disciplines. These procedures may includebut are not limited to endoscopic retrograde cholangiopancreatography(ERCP) for placement into the biliary tree or pancreas, transseptalpuncture for placement into the arterial portion of the cardiovascularsystem, lumbar puncture into the cerebrospinal fluid, and cystoscopy forplacement into the urinary tract.

In some embodiments of the invention, the proximal end of the probe hasa closed end without an electrical or fiberoptic connector. The proximalends of the lead wires or fiberoptic lines terminate in a receiving andstorage assembly that is capable of receiving the impedance or opticalinformation detected by the probe and to store the data for retrieval ata later date. In a further embodiment of the invention, the receivingand storage assembly further comprises a wireless transmitter fortransmitting the data to a remote base. Wireless transmission is wellknown in the art. For example, a Bluetooth wireless system may be usedto transmit data from the probe to a computer or remote base.

E. Ex Vivo Probe Assessment

The capture of nucleic acids from an in vivo device can be monitored exvivo using standard qualitative and quantitative molecular assays. Theassays can directly measure the nucleic acids or amplify them to measurethem. The assays can be probe-, sequence- or affinity ligand-based. Theassessment of DNA/RNA in body fluids ex vivo is known and currentlyavailable. These include but are not limited to gel electrophoresis,real time quantitative polymerase chain reaction (PCR), probe basedchromatographic assays. For DNA analysis, this will includemicrosatellite analysis for loss of heterozygosity or by singlenucleotide polymorphism (SNP). Other DNA markers can include mutations,amplifications, insertions and translocations. This may be specific ormultiple sites of the DNA from tumor cells. RNA analysis will involveassessment of mRNA of transcripts of specific genes related to the tumorcells. The mRNA transcript may be of the whole or part of the fulltranscript or a truncated derivative of the transcript. The proceduremay also include chromatin and DNA complexes related to specific genomicregions of tumor cells. The procedure may also include assessment ofacetylated and de-acetylated or modified regions of the chromatin andhistones surrounding a specific gene. The procedure may also includeassessment of methylation or demethylation of gene promoter regions.

As mentioned previously, separating and/or distinguishing a boundbinding partner from an unbound binding partner on the probe is known inthe art. In some embodiments of the invention, the unbound antibody isseparated from the probe while the CMC-bound antibody remains on theprobe. An impedance measurement system may then be used to analyze thepresence of remaining bound antibody on the probe.

Assessment of antibody or protein-based markers is currently availableand may include but is not limited to affinity binding assays, massspectroscopy, and ELISA. Similarly, carbohydrate markers are also knownand may include affinity or ligand-based capture assays and massspectroscopy. One skilled in the art can select one or more assays basedupon the particular marker or markers of interest.

One embodiment of the invention comprises a percutaneously insertabledevice used with injectable antibodies that recognize tumor-related cellsurface proteins/glycoproteins (i.e.: cMet, HER2/neu, beta-Humanchorionic gonadotropin (HCG), MUC-1, etc) or glycolipids (gangliosidesGM2, GD2). The antibodies can capture and bind the circulating tumorcells in the blood or body fluid. Single or multiple antibodies to aspecific cell surface marker or multiple markers may be used. Theattraction device or catheter with the attracted tumor cells can beremoved and subjected to standard ex vivo isolation methods known in theart for RNA, DNA, carbohydrate and protein isolation and purification.The isolation of these cell products is one approach to identify theirspecificity. Another approach is to isolate the cells and assess them aswhole cells. These approaches are advantageous in providing a unique invivo enrichment method for the collection of circulating tumor cells andtheir subcomponents, such as DNA, RNA and proteins, for furtherevaluation and assessment.

In some embodiments, the cells can be separated from the device byturning off the active attraction force created by an electromagneticattraction site on the device. Once separated from the device, the cellscan undergo respective component isolation. In other embodiments, thecells are analyzed while still attached to the device. In one example,cells can be processed, purified and quantitated for specific nucleicacids such as RNA and DNA by methods known in the art. To assess theamount of nucleic acids, one can perform qualitative and/or quantitativeanalysis for specific RNA and DNA markers that are tumor-related. Thesemarkers may be different from the antibody specific markers that areused to capture the cells. The antibody used to capture markers may alsobe used.

In one embodiment, cells are captured using antibody to c-Met, thenassessment for cMet mRNA expression in the cells is performedqualitatively or quantitatively by realtime PCR. PCR providesamplification of the target mRNA marker and allows for detection throughmany available approaches including but not limited to as gelelectrophoresis, realtime PCR thermocyclers, etc.

In one embodiment, tumor mRNA markers for assessment can include markersmost prevalent in the type of cancer being assessed. For example, inmelanoma one could assess for MART-1 mRNA. For breast cancer one canassess mammoglobin. Less prevalent markers may also be used.Quantitative marker detection may be used to rule out false positives.This provides another layer of specificity to the detection scheme.Also, to increase the sensitivity of the detection scheme, multiplemarkers can be used to assess for isolated tumor cells. One can alsoassess for specific DNA markers such as mutations, loss ofheterozygosity, amplification, translocation, etc. Specific geneticchanges may be related to specific cancers or groups of cancers.Specific genetic changes can be used in combination with multiple markerdetection approaches. Some examples include detection of BRAF mutationat V600 for melanoma, methylation of RASSF1a promoter site, or LOH at9p21. The use of specific nucleic markers can be used to determinespecific types of cancers, level of disease malignancy, diseaseaggressiveness, prognostic and predictive values and other information.

In one approach, proteins are isolated and purified by direct isolation.These proteins can be assessed by ELISA for specific tumor markers,Western Blot approaches, mass spectrometry, protein arrays,ProteinChips, antibody based assays, affinity protein based assays, etcin a quantitative and qualitative manner. The approaches can be used forglycoproteins and other carbohydrate markers. The use of specificprotein/glycoprotein/carbohydrate markers can be used to determinespecific types of cancers, level of disease malignancy, diseaseaggressiveness, prognostic and predictive values and other information.

Another approach is to elute the cells. Cells attracted to the cathetercan be evaluated using conventional histopathologic andimmunocytochemical staining methods that characterize the collectedcells of interest. These cells can be evaluated directly on the catheteror, in one embodiment, the cells are separated from the catheter byinactivating the attraction force. Standard methods to disrupt tumorcell complementary antibody binding may then be used to separate, forexample, the antibody/magnetic particle combination from the tumor cell.Current methods include mechanical separation (such as scraping and/orwashings with saline, buffered solutions, or media), chemicaldissociation techniques such as washing the catheter/antibody/tumor cellcomplex with pH buffered solutions (such as PBS with EDTA or salts thatdisrupt antibody binding to cells but not destroy the cells, etc.), thusallowing the cells to be collected intact after separation from theantibody and assessed by conventional methods such as immunostainingprocedures. In still another embodiment, cells may also be released bydisrupting the antibody-cell complex from the device. After isolation,the cells can be immunostained with specific antibodies against tumorcell surface markers or intracellular markers. The assessment of tumorcells may be performed by conventional immunopathology for tumor celldiagnosis, but other approaches are known in the art, including but nolimited to immunostained cells by FACs analysis. In these approaches,multiple antibodies can be used for detection to improve sensitivity andspecificity for specific cells. Also, some approaches allow detection ofthe number of cells detected for quantitation of disease level. Cellscan be also assessed by conventional or non-conventional stains and dyesthat are not antibody-based. Still another approach is in situhybridization with nucleic acids or derivative molecules that arecomplimentary. The above approaches for detection of eluted cells,intact or not intact, for specific components (protein, nucleic acids,etc) can be approached quantitatively or qualitatively. The approachescan be by individual or combination of methods.

While this invention has been particularly shown and described withreferences to embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the scope of the invention. For all ofthe embodiments described above, the steps of the methods need not beperformed sequentially.

1. A biological surveillance probe for detecting disease, comprising anelongate body having a proximal end and a distal end; an attractionstructure attached to the elongate body, wherein the attractionstructure is capable of attracting a binding agent.
 2. The probe ofclaim 1, wherein the attraction structure is a magnetizable structure.3. The probe of claim 2, wherein the attraction structure comprises amicro structure.
 4. The probe of claim 5, wherein the attractionstructure comprises a nanotube micro structure.
 5. The probe of claim 2,wherein the attraction structure is a metallic microporous structure. 6.The probe of claim 2, wherein the attraction structure is a cavitycontaining a mixture of a polymer gel and magnetizable particles.
 7. Theprobe of claim 1, further comprising a detection assembly.
 8. The probeof claim 7, further comprising an electrical detection assembly.
 9. Theprobe of claim 8, wherein the detection assembly is an impedance-baseddetection assembly.
 10. The probe of claim 8, wherein the detectionassembly is an ion-exchange membrane detection assembly.
 11. The probeof claim 7, wherein the detection assembly is a fiberoptic-basedassembly.
 12. The probe of claim 1, further comprising a binding agent.13. The probe of claim 12, wherein the binding agent comprises anantibody.
 14. The probe of claim 12, further comprising a fluorescentdye component linked to the binding agent
 15. The probe of claim 12,further comprising a quantum dot component linked to the binding agent.16. The probe of claim 1, wherein the elongate body comprises astent-like structure.
 17. The probe of claim 16, wherein the attractionstructure comprises a magnetizable coating on the elongate body.
 18. Amethod for detecting disease, comprising the steps of: providing abinding agent attraction device; inserting the device into a body;introducing a binding agent into the body; attracting at least a portionof the binding agent to the attraction device; and assessing the bindingagent attracted to the attraction device.
 19. The method of claim 18,wherein the introducing step is performed by injecting the binding agentinto the bloodstream.
 20. The method of claim 18, wherein theintroducing step is performed by an eluting the binding agent from animplant within the body.
 21. The method of claim 18, wherein theintroducing step is performed by ingestion of the binding agent into thebody.
 22. The method of claim 18, wherein the assessing step isperformed by impedance-based detection of the binding agent.
 23. Themethod of claim 18, wherein the assessing step is performed by opticaldetection of the binding agent.
 24. A method for detecting disease,comprising the steps of: introducing a binding agent into the body;attracting at least a portion of the binding agent to a location in thebody; and assessing the attracted binding agent.
 25. The method of claim24, wherein the assessing step is performed ex vivo.
 26. The method ofclaim 24, wherein the assessing step is performed in vivo.
 27. Themethod of claim 24, wherein the location in the body is the position ofan attraction device placed within the body.
 28. The method of claim 24,wherein the binding agent is linked to a fluorescent dye.
 29. The methodof claim 28, wherein the assessing step is performed by assessing thefluorescence of the fluorescent dye levels of the attracted bindingagent.